The Community Enterprise Operating System, commonly known as CentOS is a solid Linux Operating system similar to Red Hat Linux. We recently ran into a GUI boot problem after upgrading to CentOS 6.4 in a VirtualBox environment. Upon restarting after the upgrade, we noticed that during the boot process, the system showed either a blank screen or the CentOS progress bar for an extended period, almost one hour.
Apparently, the CentOS 6.4 upgrade broke X11 (the UNIX/Linux Graphical User Interface or GUI). A few attempts at repairing the boot loader using the CentOS 6.4 installation disc did not help.
